General Description

The DS1343/DS1344 low-current real-time clocks (RTCs) are timekeeping devices that provide an extremely low standby current, permitting longer life from a backup supply source. The devices also support high-ESR crystals, broadening the pool of usable crystals for the devices. The clock/calendar provides seconds, minutes, hours, day, date, month, and year information. The date at the end of the month is automatically adjusted for months with fewer than 31 days, including corrections for leap year. The clock operates in either 24-hour or 12-hour format with an AM/PM indicator.

Features

♦ Low Timekeeping Current of 250nA (typ)

♦ Compatible with Crystal ESR Up to 100kΩ

♦ Versions Available to Support Either 6pF or 12.5pF Crystals

♦ RTC Counts Seconds, Minutes, Hours, Day, Date, Month, and Year with Leap Year Compensation Valid Through 2099

♦ Power-Fail and Switch Circuitry

♦ Three Operating Voltages

    1.8V ±5

    3.0V±10

    3.3V ±10

♦ Trickle-Charge Capability

♦ Maintain Time Down to 1.15V (typ)

♦ Support Motorola SPI Modes 1 and 3, or Standard 3-Wire Interface

♦ Burst Mode for Reading/Writing Successive Addresses in Clock/RAM

♦ 96-Byte Battery-Backed NV RAM for Data Storage

♦ Two Time-of-Day Alarms with Two Interrupt Outputs

♦ Industrial Temperature Range

♦ 20-Pin TSSOP or 14-Pin TDFN Package

♦ Underwriters Laboratories (UL) Recognized

Applications

    Medical

    Handheld Devices

    Telematics

    Embedded Timestamping